Field of the Invention
The invention relates to an active pixel sensor, and more particularly, to an active pixel sensor which comprises more sensing pixels and has better transmittence.
Description of the Related Art
Complementary metal oxide semiconductor (CMOS) image sensors have been widely used in a variety of applications, such as digital cameras and deoxyribonucleic acid (DNA) sensors, for example. Generally, each pixel on a sensing panel of a CMOS image sensor comprises a sensing element and other elements generating a corresponding sensing signal. As the size of the CMOS image sensor gets smaller, the size of the sensing element in each pixel must be reduced (that is, the fill rate is reduced). Moreover, the sensing panel is converted with metal wires which are connected with the pixels. These metal wires disadvantageously affect the light transmission of the sensing panel, which causes a dispersion phenomenon. Thus, the amount of light sensed by each pixel is reduced, which degrades the sensing accuracy of the CMOS image sensor.